This invention relates to a method of growing regular arrays of grain boundary free single crystal silicon islands in a silicon-on-insulator film.
In a standard method for making single crystal silicon islands, a patterned antireflection coating is used to define single crystal island areas. The antireflective coating pattern is made up of a series of stripes which are deposited over a layer of polysilicon. A laser beam is then scanned parallel to the antireflective stripes thereby producing a single crystal silicon island between the antireflective stripes [see e.g., J. P. Colinge, E. Demoulin, D. Bensahel, and G. Auvert, "Use of Selective Annealing for Growing Very Large Grain Silicon-On-Insulator," Applied Physics Letter, Vol. 41, No. 14 pp.346-347, August 1982; J. P. Colinge, E. Demoulin, D. Bensahel, G. Auvert, and H. Morel, "Transistors Made in Single-Crystal SOI Films," IEEE Electron Device Letters, Vol. EDL-4, No. 4 April 1983]. Other methods for growing single crystal silicon islands in a silicon-on-insulator film are described in an article by G. K. Celler, L. E. Trimble, K. K. Ng, H. J. Leamy and H. Baumgart entitled "Seeded Oscillatory Growth of Si Over SiO.sub.2 by CW Laser Irradiation," in Applied Physics Letter, Vol. 40, No. 12, June 1983.
One of the drawbacks of the above method is the difficulty of obtaining high quality single crystal silicon near the edges of the beam. In addition, overlapped successive scans can destroy the single crystal produced by the earlier scans causing random nucleation in the overlap region. This random nucleation prevents the making of single crystal silicon regions larger than 30 microns in width.